Computational phonon dispersions structural and thermodynamical characteristics of novel C-based XC (X = Si, Ge and Sn) materials

Abstract

A realistic rigid-ion-model (RIM) is adopted here to report the results of systematic calculations for comprehending the phonon dispersionsωjq→, structural, and thermodynamic traits of novel zinc-blende group-IV binary XC (X = Si, Ge, and Sn) materials. At ambient pressure, our study of ωjq→ has offered positive values of the acoustic phonon frequencies in the entire Brillouin zone – implying the structural stability of these zinc-blende (zb) semiconductors. In the absence of experimental data for GeC and SnC on Born’s transverse effective charges eT*, T-dependent Debye temperatures ΘDT, specific heats CvT, and thermal expansion coefficients α(T), our predicted results are consistent with the existing ab initio calculations. Large deviations in ΘDT offered by a few authors are probably linked to their use of simple analytical expressions. In agreement with the first principles calculations on 3 C-SiC, our study has provided accurate T-dependent thermodynamic quantities. As compared to 3 C-SiC, we have predicted substantially lower (higher) ΘDT (α(T)) values for the zb GeC and zb SnC. Based on these outcomes, it is likely that these materials might not support the required criterion for their use as fuel cladding and/or structural materials in nuclear reactors. However, we strongly feel that these C-based compounds will be valuable in designing multi-quantum well and superlattice-based micro-/nano devices for different strategic and civilian applications needs.